1. Field of the Invention
The present invention relates to a heater block used in semiconductor manufacturing devices such as wire bonders, etc.
2. Prior Art
A conventional heater block in wire bonding machines selectively uses a multiple number of heater plates. When there is a change in the type of lead frames upon which bonding is to be performed, one of the heater plates which most matches the lead frames is selected and installed on a heater block body which contains a heater.
Japanese Utility Model Application Publication ("Kokoku") Nos. 1-42352 (called "Example 1") and 57-54278 (called "Example 2") disclose heater blocks having the structure described above. Example 1 uses two pins for horizontal positioning of the heater plate on the heater block body. In Example 2, the heater plate is fastened to the heater block body via screws.
These conventional examples have several problems. In Example 1, since the heater plate is merely placed at a specified position on the heater block body, the heater plate may float upwardly with respect to the heater block body. Thus, the bonding reliability tends to be low.
Contrarily, in Example 2, the heater plate is installed to the heater block body via screws. Accordingly, the heater plate is tightly fastened to the heater block body, and there are no such problems as seen in Example 1. However, since such a fastening in Example 2 is accomplished by means of screws, replacement of the heater plate requires a considerable amount of time.